----- Original Message ----

quoted text
> From: Stuart Henderson <stu@spacehopper.org>
> To: James Peltier <james_a_peltier@yahoo.ca>
> Cc: Andre Keller <ak@list.ak.cx>; misc@openbsd.org
> Sent: Wed, September 22, 2010 12:31:43 PM
> Subject: Re: em(4) ierrs [solved]
> 
> 
> the "livelock" counter means a timeout wasn't  reached in time,
> indicating the system being too busy to run  userland.
> (see m_cltick(), m_cldrop() etc in sys/kern/uipc_mbuf.c,
> and the  video from asiabsdcon starting about 15 minutes into
> http://www.youtube.com/watch?v=fv-AQJqUzRI).
> 
> when this happens, nics  with drivers using the MCLGETI mechanism
> halve the size of their receive  rings, so that packets drop
> earlier, more effectively limiting system load  than if they
> were allowed to proceed up the network stack.
> 
> so for some  reason or other the timeout wasn't processed
> quickly enough and the system  responds in this way to limit
> the overload. so the challenge is to identify  what causes
> the system to become non-responsive (could be in the  network
> stack or could be for other reasons) and work out ways
> to  alleviate that..
> 
>

Thanks for the notes.  Below are snapshots of vmstat -i and systat vmstat which 
do show "high" interrupt levels (6-12k).  I put quotes around high because I'm 
not really sure if that is high.

That said, is there any benefit to the use of blocknonip clause being added to 
the bridge devices?

I also note, that according to the m_cldrop() that the "halving" is done on all 
interfaces.  This seems odd, in that, if you had a device with multiple cards 
that all traffic would be affected at the expense of one.  Am I correct in this?


# vmstat -i
interrupt                       total     rate
irq0/clock                  819075628      199
irq0/ipi                     20855029        5
irq112/em0                12478765512     3047
irq113/em1                13607027530     3322
irq113/bge1                  12635532        3
irq97/uhci1                      1949        0
irq96/ehci0                        22        0
irq98/pciide0                 5204039        1
irq145/com0                       339        0
Total                     26943565580     6578


and

#systat vmstat

   1 users    Load 0.64 0.67 0.66                      Wed Sep 22 16:56:35 2010

            memory totals (in KB)            PAGING   SWAPPING     Interrupts
           real   virtual     free           in  out   in  out    11067 total
Active    15388     15388  2918228   ops                            200 clock
All      383480    383480  6585880   pages                           48 ipi
                                                                   5586 em0
Proc:r  d  s  w    Csw   Trp   Sys   Int   Sof  Flt     1 forks    5212 em1
           7       101   561  1525  9438   105  595       fkppw      21 bge1
                                                          fksvm         uhci1
  18.8%Int   1.3%Sys   1.9%Usr   0.0%Nic  77.9%Idle       pwait         ehci0
|    |    |    |    |    |    |    |    |    |    |       relck         pciide0
|||||||||=>                                               rlkok         com0
                                                          noram
Namei         Sys-cache    Proc-cache    No-cache      96 ndcpy
    Calls     hits    %    hits     %    miss   %      18 fltcp
       55       55  100                               106 zfod
                                                       31 cow
Disks   wd0   cd0                                   27514 fmin
seeks                                               36685 ftarg
xfers                                                     itarg
speed                                                  17 wired
  sec                                                     pdfre
                                                          pdscn
                                                          pzidle
                                                       13 kmapent


---
James A. Peltier     james_a_peltier@yahoo.ca8